<template>
  <div class="upload-file">
    <el-upload
      multiple
      :action="uploadFileUrl"
      :before-upload="handleBeforeUpload"
      :file-list="fileList"
      :limit="limit"
      :on-error="handleUploadError"
      :on-exceed="handleExceed"
      :on-success="handleUploadSuccess"
      :show-file-list="false"
      :headers="headers"
      class="upload-file-uploader"
      ref="fileUpload"
    >
      <!-- 上传按钮 -->
      <el-button type="primary">选取文件</el-button>
    </el-upload>
    <!-- 上传提示 -->
    <div class="el-upload__tip" v-if="showTip">
      请上传
      <template v-if="fileSize"> 大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b> </template>
      <template v-if="fileType"> 格式为 <b style="color: #f56c6c">{{ fileType.join("/") }}</b> </template>
      的文件
    </div>
    <!-- 文件列表 -->
    <transition-group class="upload-file-list el-upload-list el-upload-list--text" name="el-fade-in-linear" tag="ul">
      <li :key="file.uid" class="el-upload-list__item ele-upload-list__item-content" v-for="(file, index) in fileList">
        <el-link :href="`${baseUrl}${file.url}`" :underline="false" target="_blank">
          <span class="el-icon-document"> {{ getFileName(file.name) }} </span>
        </el-link>
        <div class="ele-upload-list__item-content-action">
          <el-link :underline="false" @click="handleDelete(index)" type="danger">删除</el-link>
        </div>
      </li>
    </transition-group>
  </div>
</template>

<script setup>
  import { getToken } from "@/utils/auth"

  const props = defineProps({
    modelValue: [String, Object, Array],
    // 数量限制
    limit: {
      type: Number,
      default: 5
    },
    // 大小限制(MB)
    fileSize: {
      type: Number,
      default: 5
    },
    // 文件类型, 例如['png', 'jpg', 'jpeg']
    fileType: {
      type: Array,
      default: () => ["doc", "xls", "ppt", "txt", "pdf"]
    },
    // 是否显示提示
    isShowTip: {
      type: Boolean,
      default: true
    }
  })

  const { proxy } = getCurrentInstance()
  const emit = defineEmits(['update:modelValue'])
  const number = ref(0)
  const uploadList = ref([])
  const baseUrl = import.meta.env.VITE_APP_BASE_API
  const uploadFileUrl = ref(import.meta.env.VITE_APP_BASE_API + "/common/upload") // 上传文件服务器地址
  const headers = ref({ Authorization: "Bearer " + getToken() })
  const fileList = ref([])
  const showTip = computed(
    () => props.isShowTip && (props.fileType || props.fileSize)
  )

  watch(() => props.modelValue, val => {
    if (val) {
      let temp = 1
      // 首先将值转为数组
      const list = Array.isArray(val) ? val : props.modelValue.split(',')
      // 然后将数组转为对象数组
      fileList.value = list.map(item => {
        if (typeof item === "string") {
          item = { name: item, url: item }
        }
        item.uid = item.uid || new Date().getTime() + temp++
        return item
      })
    } else {
      fileList.value = []
      return []
    }
  }, { deep: true, immediate: true })

  // 上传前校检格式和大小
  function handleBeforeUpload(file) {
    // 校检文件类型
    if (props.fileType.length) {
      const fileName = file.name.split('.')
      const fileExt = fileName[fileName.length - 1]
      const isTypeOk = props.fileType.indexOf(fileExt) >= 0
      if (!isTypeOk) {
        proxy.$modal.msgError(`文件格式不正确, 请上传${props.fileType.join("/")}格式文件!`)
        return false
      }
    }
    // 校检文件大小
    if (props.fileSize) {
      const isLt = file.size / 1024 / 1024 < props.fileSize
      if (!isLt) {
        proxy.$modal.msgError(`上传文件大小不能超过 ${props.fileSize} MB!`)
        return false
      }
    }
    proxy.$modal.loading("正在上传文件，请稍候...")
    number.value++
    return true
  }

  // 文件个数超出
  function handleExceed() {
    proxy.$modal.msgError(`上传文件数量不能超过 ${props.limit} 个!`)
  }

  // 上传失败
  function handleUploadError(err) {
    proxy.$modal.msgError("上传文件失败")
  }

  // 上传成功回调
  function handleUploadSuccess(res, file) {
    if (res.code === 200) {
      uploadList.value.push({ name: res.fileName, url: res.fileName })
      uploadedSuccessfully()
    } else {
      number.value--
      proxy.$modal.closeLoading()
      proxy.$modal.msgError(res.msg)
      proxy.$refs.fileUpload.handleRemove(file)
      uploadedSuccessfully()
    }
  }

  // 删除文件
  function handleDelete(index) {
    fileList.value.splice(index, 1)
    emit("update:modelValue", listToString(fileList.value))
  }

  // 上传结束处理
  function uploadedSuccessfully() {
    if (number.value > 0 && uploadList.value.length === number.value) {
      fileList.value = fileList.value.filter(f => f.url !== undefined).concat(uploadList.value)
      uploadList.value = []
      number.value = 0
      emit("update:modelValue", listToString(fileList.value))
      proxy.$modal.closeLoading()
    }
  }

  // 获取文件名称
  function getFileName(name) {
    if (name.lastIndexOf("/") > -1) {
      return name.slice(name.lastIndexOf("/") + 1)
    } else {
      return ""
    }
  }

  // 对象转成指定字符串分隔
  function listToString(list, separator) {
    let strs = ""
    separator = separator || ","
    for (let i in list) {
      if (list[i].url) {
        strs += list[i].url + separator
      }
    }
    return strs != '' ? strs.substr(0, strs.length - 1) : ''
  }
</script>

<style scoped lang="scss">
.upload-file-uploader {
  margin-bottom: 5px;
}
.upload-file-list .el-upload-list__item {
  border: 1px solid #e4e7ed;
  line-height: 2;
  margin-bottom: 10px;
  position: relative;
}
.upload-file-list .ele-upload-list__item-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: inherit;
}
.ele-upload-list__item-content-action .el-link {
  margin-right: 10px;
}
</style>
